<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>菜鸟教程(runoob.com)</title>
    <style>
        /* 下拉菜单（select）样式 */
        select {
            width: 100%;
            padding: 16px 20px;
            border: none;
            border-radius: 4px;
            background-color: #f1f1f1;
        }
    </style>
</head>

<body>

    <p>下拉菜单</p>

    <form>
        <select id="country" name="country">
            <option value="au">Australia</option>
            <option value="ca">Canada</option>
            <option value="usa">USA</option>
        </select>
    </form>

</body>

</html>